The purpose of this experiment was to determine the effects of various surface treatments on veneering resin to metal bond for Ni-Cr alloy.
The metal surfaces were treated as follows.
Group 1 : Ground with carborudum point and followed by silicoating
Group 2 : Sandblasted with 50 ㎛ aluminum oxide and followed by silicoating
Group 3 : Sandblasted with 250 ㎛ aluminum oxide and followed by silicoating
Group 4 : Beaded with 200 ㎛ retention structures and followed by silicoating
Group 5 : Silicoated in as cast condition
Group 6 : Beaded with 200 ㎛ retention structures only
All specimens were veneered with resin. Each group was consisted of 20 specimens. 10 specimens were storaged in 37℃ water for 3 days and the rest 10 specimens were thermocycled 1000 times at temperature of 5℃ to 55℃. The effects of various surface treatments on the bond strength between resin and metal interface were studied by means of four-point flexure test.
The specimens which had been ground with carborundum point, sandblasted with 50 ㎛ and 250 ㎛ aluminum oxide, beaded with 200 ㎛ retention structures and not been treated were observed with SEM.
The following results were obtained
1. The bond strength of groups 2, 3, 4 and 6 were higher than the that of groups 1 and 5 (p<0.05) in the case of being storaged in 37℃ water for 3 days, and there was no statistically significant difference in bond strength among groups 2, 3, 4 and 6, and between groups 1 and 5(p>0.05).
2. The bond strength of the case of being thermocycled decreased in the following orders : groups 2, group 4, group 3, group 6, group 1, group 5 and there was no statistically significant difference in bond strength among groups 2, 3 and 4, between groups 1 and 5(p>0.05).
3. A statistical difference in bond strength of each group between being storaged and being thermocycled was demonstrated for group 5(p<0.05).
4. The treated surfaces of groups 2, 3 and 4 had more fine undercut than the that of groups 1 and 5 with SEM.
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